Sterling International Battery Charger - Wiring Question

[swifty]

My boat new to me has a Sterling International Battery Charger 30 Amps fitted. The power cables from the charger run to the positive terminals of the batteries and the negative cable to the negative terminal. There are no inline fuses fitted, on checking the Sterling Web site the diagram shows a inline fuse fitted in the negative line.

I have never seen an inline fuse fitted in a negative line is this correct and how does it work.

Can forum members please advise.

 

[VicS]

Because there is no mention of a 30 amp charger in the "International" range I looked at the details of the "Pro-digital" range, which is a technical upgrade of the International range.

I found that the negative is fused externally because it is a requirement of the ABYC
and the explanation:
<span style="color:blue">"Negative Fused externally (A.B.Y.C requirement)
Because the largest market for our products is in the USA, it is important to conform to European and USA standards. This is a requirement for the USA A.B.Y.C boat building code of practice, as a result some electricians were receiving electric shocks because they thought they were on the DC negative system when they were on the 110V AC system (guaranteed to wake you up first thing in the morning). As a result international regulation bodies are attempting to change the colour of the DC negative cables (which have been black) to yellow, this is already the case in the USA for ABYC and is under review in the UK. The negative cable in the new digital range comes as yellow and a gold fuse is supplied."</span>

Not that that helps much!

I also found in the installation instructions the statement:
<span style="color:blue">" It is also recommended that all the charger outputs have a fuse"</span>

Personal opinion only, but because the ABYC requirement does not apply to an installation in the UK I would probably not bother with the fuse in the negative BUT I would definitely fit fuses in all the positive connections, and fit them as close as possible to the battery connections.

 

[markdj]

I would say that 98% of battery chargers are not fitted with fuses/circuit breakers and also 99.9% of alternators are not wired with fuses.

It is generally not a requirement but if the fuse is fitted and comes with it then there's no harm in having it.